Tethering options??

Hey y'all. I got my iPad 2 3G AT&T. I have an iPhone 4 and am grandfathered into unlimited data. Should I activate my iPad 3G or tether? If I tether, will I give up my unlimited data? Cost comparison? I only need to use 3G occasionally such as on Vacation etc. I am usually around WiFi. I am not interested in jail breaking anything.
I appreciate your thoughts.
Great forum.
Mike

Yup I know I need to pay the tethering charge but if I just activate 3G I have to pay a monthly charge as well. I had heard that if I tether to my iPhone, I would lose my grandfathered unlimited data. I just thought someone might know off the top of their heads.
Thanks,
Mike

I work EMS and I'm in a ambulance for about 16 hours a shift. I had like you the unlimited plan on my phone and bout the 3G 64gb iPad. It was cheaper for me to pay $45 for 4gb and teathering then to keep the unlimited plan AND $$$ for only 2gb of data direct to the iPad.

I have been tethering to my iPhone since day one and haven't had any "serious" issues. However from time to time I have had to enable/turn off my button on the phone to connect. But no other issues, works great and I LOVE IT!!!